Operating systems and applications often need to be upgraded. In order to ensure that all users can use an updated application or an updated operating system normally after an upgrade, a grayscale-upgrade can be performed to a few users before all users are upgraded. Grayscale-upgrade is a smooth switching during an upgrade.
According to related art, if an operating system or an application needs to be upgraded, a grayscale-upgrade is first performed to several terminal devices as a test. Then, according to results of the grayscale-upgrade, other devices are upgraded, to ensure that there is no problem in the upgrade. That is, instead of upgrading all the terminal devices at the same time, several terminal devices are upgraded first, and then other terminal devices are upgraded. During a grayscale-upgrade, a server needs to obtain an identification of each terminal device participating in the grayscale-upgrade and to send a grayscale-upgrade notification to each terminal device participating in the grayscale-upgrade. The terminal devices participating in the grayscale-upgrade are then upgraded according to the notifications. However, some devices are not suitable for grayscale-upgrade, such that an intended result cannot be achieved.